STP1256

    Evaluation of Test Methods for Dynamic Toughness Characterization of Duplex Stainless Steel Forgings

    Published: Jan 1995


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    Abstract

    Ferralium is a dual-phase stainless steel which consists of roughly equal amounts of ferrite and austenite. Conventional Charpy V-notch impact tests were performed on specimens taken from several locations in three orientations from a forged Ferralium plate to quantify the materials dynamic fracture performance. The Charpy tests were compared with 2.54 cm thick (1T) single edge bend (SE(B)) specimens that were tested in a drop tower to measure dynamic fracture initiation toughness (KId). SE(B) specimens were removed from three plate locations and tested in a single orientation. Charpy and KId tests were performed over the entire fracture mode transition temperature range, but the bulk of testing was concentrated at a single temperature \t-2‡C to provide a statistically significant number of tests at a representative point in the ferritic fracture mode transition region. Charpy impact energy varied consistently with both orientation and location within the forged plate even though large scatter was present in the results. This large scatter precluded an accurate assessment of the materials fracture performance within the transition region. The scatter in the drop tower (SE(B)) results was much less and indicated that plate location had a minimal affect on performance. The reduced scatter in the SE(B) specimens is attributed to two factors. First, the microstructure of Ferralium, while macroscopically homogeneous, contains ferritic and austenitic phase sizes that approach the dimensions of the standard Charpy specimen. Second, the Charpy testing technique causes more variation than the standard SE(B) KId tests within the transition region.

    Keywords:

    Duplex stainless steel, Ferralium 255, Dynamic fracture toughness, Impact toughness, Fracture safety assessment


    Author Information:

    Natishan, ME
    Assistant Professor, University of Maryland, College Park, MD

    Tregoning, RL
    Mechanical Engineer, Naval Surface Warfare Center, Annapolis, MD


    Paper ID: STP16415S

    Committee/Subcommittee: E08.03

    DOI: 10.1520/STP16415S


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